Why move from Metal to Composites?
Most people move from metal into composites because they have a specific need:
1. To reduce the weight of a component
Specific strength - this is defined as the strength of the material divided by its weight. Effectively composites' strength to weight ratio is significantly greater than its metal counterpart which is why we have replaced metal parts from aluminum through to titanium using composite tubes. Local reinforcements are also available where required.
2. Improved resistance to corrosion
In normal and aggressive environments composites have a much greater resistance to corrosion. A good example of this is the extensive use of composites in marine and aerospace applications.
3. Increased resistance to repetitive strain
Composites unlike metal can be designed to have extensive deformation without taking a permanent set eg it doesn't stretch like aluminium. Composites have an ability to see repetitive strain over significant time hence their use in aerospace wings and other important components.
4. Low coefficient of thermal expansion (CTE)
Depending on the fibres we use this can vary but it is significantly less than that of metals, carbon being the best at close to zero. A good example is its extensive use in the field of metrology (invar replacement).
5. X-ray Transparency
Carbon fibre is x-ray transparent and this can be of significant importance in many markets but especially medical equipment.